Here are some of the latest health and medical news developments, compiled by the editors of HealthDay:

Group Wants FDA to Ban Caramel Coloring in Sodas

The use of caramel coloring in popular soda drinks such as Coke and Pepsi should be banned due to a possible cancer risk, the consumer advocacy group Center for Science in the Public Interest says in a letter to the U.S. Food and Drug Administration.

In the letter, CSPI says lab tests found that the average level of 4-methylimidazole (4-MI) in 12-ounce servings of regular and diet Coke, Pepsi, Dr. Pepper and Whole Foods 365 cola was 138 micrograms, far above the 29 microgram limit recommended by the state of California, the Los Angeles Times reported.

The average level of 4-MI indicated a lifetime cancer risk of five out of 100,000 people, according to the letter. That risk may be higher if people who don't drink sodas aren't included in the calculation.

CSPI says 4-MI -- which is formed when sugar is mixed with ammonia and sulfites to create the caramel coloring that gives colas their familiar brown color -- has been shown to cause lung, liver and thyroid cancer in mice and rats, the Times reported.

The American Beverage Association said the CSPI letter is a "scare tactic," and noted that regulatory agencies worldwide "consider caramel coloring safe for use in foods and beverages."

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L.A. Condom Law for Porn Actors Takes Effect

A Los Angeles law requiring porn actors to wear condoms took effect Monday.

The regulation requires actors in adult movies to use condoms in order for producers to get a filming permit, the Associated Press reported.

This type of law is essential to protect porn actors from HIV and other sexually transmitted diseases, says the AIDS Healthcare Foundation, which is gathering signatures for a November ballot measure that would make condoms mandatory for adult movie actors across the United States.

Los Angeles is the nation's porn movie capital. As many as 90 percent of U.S. porn films are made in Los Angeles, according to industry leaders. They warn that the city's new law could drive adult movie production elsewhere, the AP reported.

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Confusion About Fraternal/Identical Twins Common: Study

Many parents of twins don't know if their children are fraternal or identical twins because doctors give them wrong information, according to a new study.

British researchers interviewed 1,302 parents of same-sex twins and found that 191 (14.7 percent) were misinformed, with 179 parents of identical twins told their twins were fraternal and 12 parents of fraternal twins told they were identical, The New York Times reported.

The study was published Wednesday in the journal BJOG.

"I think there are a lot of parents who just want to know," study co-author Abi Fisher, a research associate at University College London, told The Times. "A lot of parents finding out later on felt they just didn't know their own children."

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FDA Rejects New Combo Cholesterol Drug

A new combination cholesterol-lowering drug has been rejected by the U.S. Food and Drug Administration.

The drug -- called MK-0653C -- includes a generic version of Pfizer's cholesterol-lowering medicine Lipitor (atorvastatin) and Merck & Co.'s cholesterol medicine Zetia (ezetimibe). The two medicines work in different ways to lower cholesterol, the Associated Press reported.

The FDA's decision about the new combination drug -- which was created by Merck -- was announced Monday. The FDA wants additional study data on the drug.

Merck officials said they'll talk with the FDA to determine the next steps and also said that new data expected later this year may address the FDA's concerns, the AP reported.

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